[resotoworker] propagate collection progress to `resotocore`

[lloesche]

Right now the workers only log collection progress. For the UI as well as CLI it would be useful to get collection feedback so they can provide info like "Collecting AWS account 4/20" or similar. For this to work BasePlugin needs to be extended so it can feed current collection progress back to the worker and then the worker needs to forward that to the core.